We intend to investigate the basic mechanisms of cellular and humoral regulation of mouse immune interferon (IFN-gamma) production. The helper and suppressor lymphocytes that regulate IFN-gamma production will be characterized along with the IFN-gamma-producing lymphocytes. Primary T-lymphocyte lines will also be studied as possible producers and regulators of IFN-gamma production. The growth factors interleukins-1 (IL-I) and 2 (IL-2) will be investigated as possible mediators of cellular regulation of IFN-gamma production. Phorbol esters, IL-2, and polypeptide hormones such as vasopressin are cell activators and may help in IFN-gamma production through a common second messenger (cyclic GMP?). Further improvement of IFN-gamma purification and characterization will be done by lectin affinity chromatography, antibody affinity chromatography, gel electrophoresis, and N-terminal amino acid analysis. Monoclonal antibodies will be produced to IFN-gamma to improve purification and for further characterization of IFN-gamma in terms of biological activity and relationship to other lymphokines. Purified IFN-gamma should be ideal for an objective assessment of its possible range of biological activities, among which are: (1) immunoregulation; (2) antitumor and anticellular activity; (3) regulation of differentiation; and (4) antiviral properties. The mechanism of action of IFN-gamma at the molecular level will be studied (if time permits) through assessment of its membrane effects, intermediary metabolism effects, and cellular protein kinase activities. The long-term goal is to understand natural regulatory functions of IFN-gamma and to be able to manipulate IFN-gamms activity in order to obtain desirable immunological, antiviral, and antitumor activities of this lymphokine. Considerable progress has been made with regards to regulation of production of IFN-gamma. (IL-2) can replace helper cell requirement for IFN-gamma production. Dibutyryl cyclic GMP, arachidonic acid and its lipooxygenase products (such as leukotrienes), the neuropeptides: arginine, vasopressin, and oxytocin, and the tumor promoter phorbol myristic acetate can replace IL-2 requirement. IL-2 help in IFN-gamma production may involve release of second messenger signals arachidonic acid and diacyglycerol from membrane phospholipids, activation of guanylate cyclase, and activation of protein kinases such ss protein kinase C. The produced IFN-gamma was shown to cause B cell maturation. Antibodies of predetermined specificity were produced to IFN-gsmme and should help in purification and characterizstion. (HF)